92 lines
2.8 KiB
Markdown
92 lines
2.8 KiB
Markdown
# 9.练习：生成代码
|
||
|
||
*到目前为止，我们的冒险游戏有 10 个对象。每个对象由有 5 个属性组成。一个真正的文本冒险可能有数百个甚至数千个对象，并且每个对象的属性数量也可能增加（请参阅下一章）。在目前的形式下，维护如此庞大的对象和属性列表将很困难。*
|
||
|
||
例如，当我们在添加对象 *wallField* 和 *wallCave* 时，我们必须在三个不同的位置执行此操作：一次在 *object.h* 中（作为<em>#define</em>），两次在 *object.c* 中（数组 *objs* 中的一个元素，以及一个单独的标签数组）。这显然十分笨拙并且容易出错。
|
||
|
||
我们将不再手工维护 object. h 和 object. c，而是从更适合我们需要的单一源开始生成文件。这个新的源文件可以用你喜欢的任何语言 ( 典型的是某些特定领域的语言 )，只要你有工具把它转换回 C。下面是一个简单的例子，考虑下列布局来组织我们的对象：
|
||
|
||
```txt
|
||
/* Raw C code (declarations) */
|
||
- ObjectName
|
||
AttributeName AttributeValue
|
||
AttributeName AttributeValue
|
||
...
|
||
- ObjectName
|
||
AttributeName AttributeValue
|
||
AttributeName AttributeValue
|
||
...
|
||
- ...
|
||
```
|
||
|
||
根据到目前为止收集的对象，我们可以构造以下源文件。文件名并不重要;我只是简单地将其命名为*object.txt*，以明确它与*object.h*和*object.c*相关。
|
||
|
||
## object.txt
|
||
|
||
```txt
|
||
#include <stdio.h>
|
||
#include "object.h"
|
||
|
||
typedef struct object {
|
||
const char *description;
|
||
const char **tags;
|
||
struct object *location;
|
||
struct object *destination;
|
||
} OBJECT;
|
||
|
||
extern OBJECT objs[];
|
||
//对象
|
||
- field
|
||
description "an open field"
|
||
tags "field"
|
||
|
||
- cave
|
||
description "a little cave"
|
||
tags "cave"
|
||
|
||
- silver
|
||
description "a silver coin"
|
||
tags "silver", "coin", "silver coin"
|
||
location field
|
||
|
||
- gold
|
||
description "a gold coin"
|
||
tags "gold", "coin", "gold coin"
|
||
location cave
|
||
|
||
- guard
|
||
description "a burly guard"
|
||
tags "guard", "burly guard"
|
||
location field
|
||
|
||
- player
|
||
description "yourself"
|
||
tags "yourself"
|
||
location field
|
||
|
||
- intoCave
|
||
description "a cave entrance to the east"
|
||
tags "east", "entrance"
|
||
location field
|
||
destination cave
|
||
|
||
- exitCave
|
||
description "an exit to the west"
|
||
tags "west", "exit"
|
||
location cave
|
||
destination field
|
||
|
||
- wallField
|
||
description "dense forest all around"
|
||
tags "west", "north", "south", "forest"
|
||
location field
|
||
|
||
- wallCave
|
||
description "solid rock all around"
|
||
tags "east", "north", "south", "rock"
|
||
location cave
|
||
```
|
||
|
||
::: warning 🤔 思考题：你能否自己用 C 来实现这段伪代码？
|
||
:::
|